Representative for Louisiana's 2nd congressional district Congressman Cedric Richmond walks on stage before introducing Senator Elizabeth Warren at Dillard University's Georges Auditorium in New Orleans, Friday, Aug. 3, 2018. Congressman Cedric Richmond moderated a discussion with Senator Elizabeth Warren, of Massachusetts, as part of the Netroots festival.

WASHINGTON — U.S. Rep. Cedric Richmond, a New Orleans Democrat who is assistant to the House majority whip, says his "sole focus" right now is on making sure that President Donald Trump doesn't win a second term in office.

"We need to make sure that he does not win re-election," Richmond said during an appearance on CBS' Face the Nation on Sunday.

Richmond, the only Democrat in the Louisiana delegation and a former chairman of the Congressional Black Caucus, was one of the first members of Congress to endorse former Vice President Joe Biden's 2020 campaign for president.

He explained his support is based on Biden's "entire body of work."

"One thing I learned in politics very early: you can't govern if you can't win," Richmond said during the TV appearance. "And I believe Joe Biden ... is the best person to represent the Democratic Party, but I think he's the best person to win."

Richmond also said he doesn't believe that the investigation into Trump's presidential campaign and claims of connections to Russia is a settled matter after the release of a redacted version of Special Counsel Robert Mueller's report.

"This president has attempted to collude, if that's the word he wants to use. He's attempted to obstruct justice at the least. At the worst, he's obstructed justice and I believe that is the Judiciary Committee's responsibility to dig into it," Richmond said. "We have not heard from this president under oath."

Attorney General William Barr first released a summary of the Mueller report, saying it absolved the president. The full report doesn't explicitly say whether Trump should face charges or not. Barr is expected to testify before Congress this week.

Richmond said he thinks that the Democrat-controlled House should seriously consider impeachment of Trump. 

"I think it's the best way to get all of the facts out," he said. "I also believe that at some point we have to hear from this president whether he's lying to us or not. We need to hear from him under oath."

Trump, who received more than 58 percent of the vote in Louisiana in 2016, is scheduled to have a fundraiser in New Orleans on May 14. 

Follow Elizabeth Crisp on Twitter, @elizabethcrisp.